We usually call day by day for our 2-bedroom BWV reservations in late Nov/early December. Last year we decided to add a few nights to the beginning of our trip and even though it was 10 months, 28 days out, we couldn't get the std. view rooms. As it is now we're in a pref. view for the first 2 days of our trip then we switch to a std. view for the next 7 days. The points aren't so much an issue anymore - I'm just not looking forward to having to change rooms.
On the other hand, we got a std view 1-bedroom for late-June by calling in mid-January. I think it all depends on what time of year you plan on travelling. But like someone else said, if you're sure of the dates you may as well go ahead and call day by day, if for nothing else than the peace of mind.